CVE-2023-22742

libgit2 is a cross-platform, linkable library implementation of Git. When using an SSH remote with the optional libssh2 backend, libgit2 does not perform certificate checking by default. Prior versions of libgit2 require the caller to set the certificate_check field of libgit2's git_remote_callbacks structure - if a certificate check callback is not set, libgit2 does not perform any certificate checking. This means that by default - without configuring a certificate check callback, clients will not perform validation on the server SSH keys and may be subject to a man-in-the-middle attack. Users are encouraged to upgrade to v1.4.5 or v1.5.1. Users unable to upgrade should ensure that all relevant certificates are manually checked.

libgit2 is a cross-platform, linkable library implementation of Git. When using an SSH remote with the optional libssh2 backend, libgit2 does not perform certificate checking by default. Prior versions of libgit2 require the caller to set the certificate_check field of libgit2's git_remote_callbacks structure - if a certificate check callback is not set, libgit2 does not perform any certificate checking. This means that by default - without configuring a certificate check callback, clients will not perform validation on the server SSH keys and may be subject to a man-in-the-middle attack. Users are encouraged to upgrade to v1.4.5 or v1.5.1. Users unable to upgrade should ensure that all relevant certificates are manually checked.

The git2 and libgit2-sys crates are Rust wrappers around the libgit2 C library. It was discovered that libgit2 1.5.0 and below did not verify SSH host keys when establishing an SSH connection, exposing users of the library to Man-In-the-Middle attacks.

The libgit2 team assigned CVE-2023-22742 to this vulnerability. The following versions of the libgit2-sys Rust crate have been released:

• libgit2-sys 0.14.2, updating the underlying libgit2 C library to version 1.5.1.
• libgit2-sys 0.13.5, updating the underlying libgit2 C library to version 1.4.5.

A new git2 crate version has also been released, 0.16.1. This version only bumps its libgit2-sys dependency to ensure no vulnerable libgit2-sys versions are used, but contains no code changes: if you update the libgit2-sys version there is no need to also update the git2 crate version.

You can learn more about this vulnerability in libgit2's advisory

libgit2 is a cross-platform, linkable library implementation of Git. When using an SSH remote with the optional libssh2 backend, libgit2 does not perform certificate checking by default. Prior versions of libgit2 require the caller to set the certificate_check field of libgit2's git_remote_callbacks structure - if a certificate check callback is not set, libgit2 does not perform any certificate checking. This means that by default - without configuring a certificate check callback, clients will not perform validation on the server SSH keys and may be subject to a man-in-the-middle attack. Users are encouraged to upgrade to v1.4.5 or v1.5.1. Users unable to upgrade should ensure that all relevant certificates are manually checked.

libgit2 is a portable, pure C implementation of the Git core methods provided as a re-entrant linkable library with a solid API, allowing you to write native speed custom Git applications in any language which supports C bindings.

Security Fix(es):

libgit2 is a cross-platform, linkable library implementation of Git. When using an SSH remote with the optional libssh2 backend, libgit2 does not perform certificate checking by default. Prior versions of libgit2 require the caller to set the certificate_check field of libgit2's git_remote_callbacks structure - if a certificate check callback is not set, libgit2 does not perform any certificate checking. This means that by default - without configuring a certificate check callback, clients will not perform validation on the server SSH keys and may be subject to a man-in-the-middle attack. Users are encouraged to upgrade to v1.4.5 or v1.5.1. Users unable to upgrade should ensure that all relevant certificates are manually checked.(CVE-2023-22742)

libgit2 is a cross-platform, linkable library implementation of Git. When using an SSH remote with the optional libssh2 backend, libgit2 does not perform certificate checking by default. Prior versions of libgit2 require the caller to set the certificate_check field of libgit2's git_remote_callbacks structure - if a certificate check callback is not set, libgit2 does not perform any certificate checking. This means that by default - without configuring a certificate check callback, clients will not perform validation on the server SSH keys and may be subject to a man-in-the-middle attack. Users are encouraged to upgrade to v1.4.5 or v1.5.1. Users unable to upgrade should ensure that all relevant certificates are manually checked.

When using an SSH remote with the optional libssh2 backend, libgit2 does not perform certificate checking by default. (CVE-2023-22742) Using well-crafted inputs to git_index_add can cause heap corruption that could be leveraged for arbitrary code execution. (CVE-2024-24577)

These are all security issues fixed in the libgit2-1.5.1-1.1 package on the GA media of openSUSE Tumbleweed.

The git2 and libgit2-sys crates are Rust wrappers around the libgit2 C library. It was discovered that libgit2 1.5.0 and below did not verify SSH host keys when establishing an SSH connection, exposing users of the library to Man-In-the-Middle attacks.

The libgit2 team assigned CVE-2023-22742 to this vulnerability. The following versions of the libgit2-sys Rust crate have been released:

• libgit2-sys 0.14.2, updating the underlying libgit2 C library to version 1.5.1.
• libgit2-sys 0.13.5, updating the underlying libgit2 C library to version 1.4.5.

A new git2 crate version has also been released, 0.16.1. This version only bumps its libgit2-sys dependency to ensure no vulnerable libgit2-sys versions are used, but contains no code changes: if you update the libgit2-sys version there is no need to also update the git2 crate version.

You can learn more about this vulnerability in libgit2's advisory

This update for libgit2 fixes the following issues:

• CVE-2023-22742: Fixed SSH keys verification failure (bsc#1207364).

This update for libgit2 fixes the following issues:

• CVE-2023-22742: Verify ssh remote host keys (bsc#1207364)

This update for libgit2 fixes the following issues:

• CVE-2023-22742: Fixed SSH keys verification failure (bsc#1207364).

It was discovered that libgit2 mishandled equivalent filenames on NTFS partitions. If a user or automated system were tricked into cloning a specially crafted repository, an attacker could possibly use this issue to execute arbitrary code. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2020-12278, CVE-2020-12279)

It was discovered that libgit2 did not perform certificate checking by default. An attacker could possibly use this issue to perform a machine-in-the-middle attack. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, and Ubuntu 22.04 LTS. (CVE-2023-22742)

It was discovered that libgit2 could be made to run into an infinite loop. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 23.10. (CVE-2024-24575)

It was discovered that libgit2 did not properly manage memory. An attacker could possibly use this issue to cause a denial of service or execute arbitrary code. (CVE-2024-24577)